Field of the Invention
The invention relates to an electric heater for an automobile vehicle, comprising at least one heating element and at least one circuit board, with the circuit board being connected to a control unit and/or to a power supply and having at least one contact area through which an electrical connection between a heating element and a control unit and/or a power supply can be realized, the heating element possessing at least one PTC-heating element, with the heating element being connected to the circuit board with at least one connecting element.
Description of the Background Art
Electric heaters usually have at least one heating element, which can be heated by applying an electric current to the element. The heat is then transported via fins or other thermally conductive parts to a heat sink. The heat sink can thus be heated by the heating element. To control the electric current on the heating element, electric heaters also possess a control unit. This control unit is either directly connected to each heating element or via a bus bar, which is connected to the control unit and a multitude of heating elements.
Electric heaters known in the conventional art have a connection assembly between the heating elements and the control unit and/or the power supply and/or the bus bar. The connection assembly is usually built of a male connector and a female connector. Due to the nature of such a connection assembly the electric heater is exposed to mechanical stress while the connectors are being connected.
Furthermore the connection assembly can be exposed to corrosion, humidity or mechanical stress due to its location within the electric heater. Especially, if the individual heating elements are connected by a connection assembly to a common bus-system, which is connected to a power supply, the assembling of every heating element will cause mechanical stress to all the other already assembled heating elements. This can lead to damage within the connection assemblies or the heating elements.
Furthermore it is difficult to achieve a connection assembly that is sufficiently sealed off against water or humidity. The number of connections between the elements of the electric heater is usually very high, as a huge quantity of elements needs to be connected to each other, e.g. the heating elements, the bus bar, the circuit boards, the control unit and the power supply.
An entry of water or humidity can lead to fretting corrosion and hence to failure of the electric heater. Due to the environment in which such electric heaters are usually used, the connector has to fulfill a high level of requirements over the full lifetime to prevent failure. Electric heaters of this kind are usually used within automobile vehicles to support the heating of the engine or the interior of the vehicle.